Google search returns all links as "harmful"

i'm a heavy user of google search. a while ago, i noticed that all the links returned by the search engine were sub-labeled with "This site may harm your computer". clicking on the link will guide you to the google advisory page and you can't go to the site you wanted! it seems that google's server is incorrectly returning the results... maintenance or something going on???
tried searching for the key "Google", and guess what!? it was also tagged as harmful (see pix).